Added sample file for Identity Service.
Added sample file for Identity Service.

Added the policy.json file, and rearranged listing into sections.

Change-Id: Ied3775b122897b3815f62a86c01d1d2844f5f0fc
Partial-Bug: #1281348

Akasurde/openstack-manuals,openstack/openstack-manuals,saeki-masaki/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,kairoaraujo/openstack-manuals,saeki-masaki/openstack-manuals,gongysh2004/openstack-manual,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,kairoaraujo/openstack-manuals,potsmaster/openstack-manuals,openstack/openstack-manuals,gongysh2004/openstack-manual,potsmaster/openstack-manuals